Testing astcenc

The repository contains a small suite of tests which can be used to sanity check source code changes to the compressor. It must be noted that this test suite is relatively limited in scope and does not cover every feature or bitrate of the standard.

Required software

Running the tests requires Python 3.7 to be installed on the host machine, and an astcenc-avx2 release build to have been previously compiled and installed into an directory called astcenc in the root of the git checkout. This can be achieved by configuring the CMake build using the install prefix -DCMAKE_INSTALL_PREFIX=../ and then running a build with the install build target.

Running C++ unit tests

We support a small (but growing) number of C++ unit tests, which are written using the googletest framework and integrated in the CMake “CTest” test framework.

To build unit tests pull the googletest git submodule and add -DUNITTEST=ON to the CMake command line when configuring.

To run unit tests use the CMake ctest utility from your build directory after you have built the tests.

cd build
ctest --verbose

Running command line tests

To run the command line tests, which aim to get coverage of the command line options and core codec stability without testing the compression quality itself, run the command line:

python3 -m unittest discover -s Test -p astc_test*.py -v

Running image tests

To run the image test suite run the following command from the root directory of the repository:

python3 ./Test/astc_test_image.py

This will run though a series of image compression tests, comparing the image PSNR against a set of reference results from the last stable baseline. The test will fail if any reduction in PSNR above a set threshold is detected. Note that performance information is reported, but regressions will not flag a failure.

For debug purposes, all decompressed test output images and result CSV files are stored in the TestOutput directory, using the same test set structure as the Test/Images folder.

Test selection

The runner supports a number of options to filter down what is run, enabling developers to focus local testing on the parts of the code they are working on.

  • --encoder selects which encoder to run. By default the avx2 encoder is selected. Note that some out-of-tree reference encoders (older encoders, and some third-party encoders) are supported for comparison purposes. These will not work without the binaries being manually provided; they are not distributed here.
  • --test-set selects which image set to run. By default the Small image test set is selected, which aims to provide basic coverage of many different color formats and color profiles.
  • --block-size selects which block size to run. By default a range of block sizes (2D and 3D) are used.
  • --color-profile selects which color profiles from the standard should be used (LDR, LDR sRGB, or HDR) to select images. By default all are selected.
  • --color-format selects which color formats should be used (L, XY, RGB, RGBA) to select images. By default all are selected.

Performance tests

To provide less noisy performance results the test suite supports compressing each image multiple times and returning the best measured performance. To enable this mode use the following options:

  • --repeats <M> : Run M test compression passes which are timed.

Note: The reference CSV contains performance results measured on an Intel Core i5 9600K running at 4.3GHz, running each test 5 times.

Updating reference data

The reference PSNR and performance scores are stored in CSVs committed to the repository. This data is created by running the tests using the last stable release on a standard test machine we use for performance testing builds.

It can be useful for developers to rebuild the reference results for their local machine, in particular for measuring performance improvements. To build new reference CSVs, download the current reference astcenc binary (1.7) from GitHub for your host OS and place it in to the ./Binaries/1.7/ directory. Once this is done, run the command:

python3 ./Test/astc_test_image.py --encoder 1.7 --test-set all --repeats 5

... to regenerate the reference CSV files.

WARNING: This can take some hours to complete, and it is best done when the test suite gets exclusive use of the machine to avoid other processing slowing down the compression and disturbing the performance data. It is recommended to shutdown or disable any background applications that are running.

Valgrind memcheck

It is always worth running the Valgrind memcheck tool to validate that we have not introduced any obvious memory errors. Build a release build with symbols information with -DCMAKE_BUILD_TYPE=RelWithDebInfo and then run:

valgrind --tool=memcheck --track-origins=yes <command>